android - Exoplayer如何显示下载进度

Question

我正在尝试在 exoplayer 中下载离线视频，我想在 Activity 中显示下载进度。

如何绑定(bind)到 DownloadService在外层。以便我可以更新 Activity 中的当前下载进度？我尝试覆盖 onBind方法但没有onBind方法。

下载服务

class MediaDownloadService : DownloadService(
    C.DOWNLOAD_NOTIFICATION_ID, 1000,
    C.CHANNEL_ID, R.string.channel_name, R.string.channel_description
) {
    private lateinit var downloadManager: DownloadManager

    override fun onCreate() {
        downloadManager = DownloadUtil.getDownloadManager(this)
        downloadManager.addListener(object : DownloadManager.Listener {
            override fun onDownloadChanged(downloadManager: DownloadManager, download: Download) {
                if (download.bytesDownloaded == download.contentLength) {
                    toast("Download Completed!")
                }
                debug(download.failureReason)
            }
        })
        super.onCreate()
    }

    override fun getDownloadManager(): DownloadManager {
        return downloadManager
    }

    override fun getForegroundNotification(downloads: MutableList<Download>): Notification {
        val intent = Intent(this, MainActivity::class.java)
        val pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT)
        val notificationHelper = DownloadNotificationHelper(this, C.CHANNEL_ID)

        return notificationHelper.buildProgressNotification(
            R.drawable.ic_notification,
            pendingIntent,
            "simple message",
            downloads
        )
    }

    override fun getScheduler(): Scheduler? {
        return null
    }

    inner class DownloadBinder: Binder() {
        val service: MediaDownloadService
            get() = this@MediaDownloadService
    }
}

Answer 1

在 Activity 中显示当前下载进度

您需要覆盖并收听 DownloadTracker.Listener 这将使您了解下载的不同状态。

当状态为 Download.STATE_DOWNLOADING启动协程/流程以将下载的当前值发送到您的 Activity 。
我已经使用了这个流程(每 1 秒发送一次您想要的下载的 percentDownload 的值)

val downloadManager: DownloadManager // is set before in my object
suspend fun getCurrentProgressDownload(uri: Uri?): Flow<Float?> {
    var percent: Float? = downloadManager.currentDownloads.find { it.request.uri == uri }?.percentDownloaded
    return callbackFlow {
        while(percent != null) {
            percent = downloadManager.currentDownloads.find { it.request.uri == uri }?.percentDownloaded
            offer(percent)
            withContext(Dispatchers.IO) {
                delay(1000)
            }
        }
    }
}

以你喜欢的方式展示

我创建了一个存储库，您可以在其中查看 Activity 中的下载进度，这只是一个可以使用一些优化的示例。
https://github.com/yoobi/exoplayer-kotlin/tree/master/downloadvideo/src/main/java/io/github/yoobi/downloadvideo
如果有些事情不清楚，请毫不犹豫地问